Any HR professionals who have experience with unionization?

Any HR professionals who have experience with unionization?

My agency is going through unionization negotiations right now. There are a few in the mix who have used the union to begin fighting against job duties they have always had citing unfair practices. Our current attorney has been less than effective. Example, an employee had the rep - from the union who’s providing guidance - send a cease and desist because we continued the practice of assigning clients to staff based on low productivity. This is a standard practice in the field.

My question is seeking guidance on what can be demanded by staff at this time during the negotiation process. There is no contract yet with the union and we most likely will be going to arbitration. In the interim, we have a business to run but continually have the union side trying to block everyday activities. I’m trying to determine what they legally can and can’t do - and similarly, what the agency can and cannot do.

Any guidance will be greatly appreciated.